PARTIV. 
touch it again. Methods of wholesale destruction, such as the use of 
Calcium Cyanide, or hot water, would be too costly in cases of serious 
infestation, as the numbers of individual nests are very large—in 
places there may be as many as one per square yard. Furthermore 
it is only after rain when the soil is damp that the queens and the 
immature stages will be found near the surface; in dry weather the 
nests may be at’a depth of as much as a foot. Consequently the 
number of days on which such destruction could be effectively 
practised is limited. However, when a fresh outbreak of mealy-bug 
in conjunction with Pheidole is observed, it would be well worth while 
to attempt total eradication of the ants while there are still 
comparatively few nests. 
It is consequently necessary, in the majority of cases, to fall 
back on the use of repellents, and though fair results have been 
obtained from the use of a high boiling point creosote oil, it is 
unsatisfactory in many ways, the method of application being slow and 
somewhat difficult for unskilled labour, while careless use of 1t may 
result in damage at any rate to young trees. 
We have written to America for a sample of a substance used as 
a repellent against Gipsy moth caterpillars (3, p. 133), the active 
principle of which is also tar oil. It is said that this ean be applied 
direct to the bark without injury, and remains eflicient with but little 
attention for two years. Should it prove to be effective against 
Pheidole and reasonably cheap, the mealy-bug problem should be 
temporarily solved; but a permanent preventative will only be found 
when and if, by a detailed knowledge of the bionomics of this ant, the 
means can be found for its complete destruction. 
In conclusion, I wish to express my indebtedness to all the 
scientific officers of the Department of Agriculture for their invaluable 
help, more especially to Messrs. Anderson, Tox, Trench, and 
Wilkinson; and to numerous Coffee Planters, particularly to Capt K. 
E. Dormer, on whose plantation a large number of experiments have 
been conducted. 
REFERENCES. 
(1) Axperson, T. J. Report of the Entomologist. Ann. Rept., 
Dept. Agric., Kenya Colony, 1924. 
9) BorprxN, A. D. Control of the Common Mealy-bug on Citrus 
in California. U.S: Dept. Agri. Bull, No. 1309, 1923. 
3) Burcress, A. F. aNp GrirFiN, E. L.A New Tree Banding 
Material for the Control of the Gipsy Moth. = Journ. Fcon. 
Ent. Vol. X., No. 1, pp. 181—135. 1917. ; 
(4) Fousom, J. W. Entomology with Reference to its Biological 
and Economic Aspects. Philadelphia, 1913. 
(5) Kirgpatrick, T. W. The Egyptian Cotton Seed Bug. Min. 
Agric., Egypt, Bull. No. 35. 1923. 
(6) Kirgparrick, T. W. The Buff-backed Egret as a Factor in 
Egyptian Agriculture. Min. Agric. Egypt, Bull. No. 56, 1925. 
(7) LOCKHEAD, W. Class Book of Feconomic Entomology. 
Philadelphia, 1919. 
(8) Smirm, H. S. axp ArmiTace, H. M. Biological Control of 
Mealy-bugs in California. Monthly Bull. Dept. Agric., 
California IX. 4, pp. 104—158. 1920. 
‘'9) WoaruM, R. S. ano Neurs, J. D. The Common Mealy-bug 
and its Control in California. U.S. Dept. Agric. Bull No. 862. 
1017. 
194